• Vacuum Magazine
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• v.1 no.2
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• pp.24-29
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• 2014

Display is a key component in electronic devices. OLED is growing very fast recently due to the explosion of the smart phone market although still LCD is the dominating display technology in the display market at the moment. Also needs for the large area and high resolution TVs and flexible displays are increasing these days. Especially flexible display is expected to be one of the key technologies in mobile devices requiring small device size and large display size. Contrary to the conventional displays, flexible display requires organic materials for the substrate, the active driving element and also for the display element. Plastic film as a substrate, organic semiconductor as an active component of the transistor and organic light emitting materials or electronic paper as a display element are studied actively. In this article, mainly backplane technologies such as substrates and the transistor materials for flexible display will be introduced.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.598-602
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• 2002

This paper presents the 3-phase hybrid series active power filter with dynamic voltage restorer(DVR) which serve as an energy buffer and current harmonics blocking resistor connected to sensitive loads, such as, to compensate voltage dips and current harmonics in power distribution system. The DVR is to inject a dynamically controlled voltage generated by a forced commutated converter in series to the bus voltage by means of a booster transformer. The momentary amplitudes of the three injected phase voltages are controlled such as to eliminate any detrimental effects of a bus fault to the load voltage. The proposed system is able to simultaneously compensate current harmonics, voltage fluctuating and voltage unbalance in power distribution systems. The reference phase angle detected by synchronized with the positive sequence component of the unbalanced source by using symmetrical component transformation. The effectiveness of proposed system is verified by the computer simulation.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.2968-2970
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• 1999

본 논문에서는 컴포넌트 기술을 기반으로 한 인터액티브 멀티미디어 웹보드 시스템을 설계, 구현하고 있다. 이 시스템은 문서를 게시하고 파일을 첨부하는, 일반적인 웹 기반의 게시판을 확장한 것으로, 이러한 기본적 기능 외에 사용자로 하여금 동영상, 음성, 정지영상을 캡쳐하여 전송할 수 있도록 하는 기능을 제공한다. 이와 같은 작업은 ActiveX 컨트롤이 임베드된 웹 페이지 상에서 이루어지므로, 사용자에게는 브라우저 외의 별도의 프로그램이 요구되지 않는다. 이 시스템을 구성하는 주요한 기술적 요소에는 컴포넌트 기술, 웹 데이터베이스 기술 등이 있다. 컴포넌트 기술을 통해 자체적인 인터페이스를 가진 동영상 정지영상, 음성 캡쳐기능의 ActiveX 컨트롤을 구현하였고, MS SQL Server와 ASP를 이용한 웹 데이터베이스 기술을 통해 인터액티브한 인터페이스를 제공하였다.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.213-214
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• 2014

This paper compares two instantaneous reactive power definitions in DFIG wind turbine with a back-to-back three-level neutral-point clamped voltage source converter under unbalanced grid conditions. In general, conventional definition of instantaneous reactive power is obtained by taking an imaginary component of complex power. The other definition of instantaneous reactive power can be developed based on a set of voltages lagging the grid input voltages by 90 degree. A complex quantity referred as a quadrature complex power is defined. Proposed definition of instantaneous reactive power is derived by taking a real component of quadrature complex power. The characteristics of two instantaneous reactive power definitions are compared using the ripple-free stator active power control algorithm in DFIG. Instantaneous reactive power definition based on quadrature complex power has a simpler current reference calculation control block. Ripple of instantaneous active and reactive power has the same magnitude unlike in conventional definition under grid unbalance. Comparison results of two instantaneous reactive power definitions are verified through simulation.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.22.1-22
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• 2001

In this paper we present Multiple-Channel Active Noise Control[ANC] system by employing Independent Component Analysis[ICA] and Adaptive Network Fuzzy Inference System[ANFIS]. ICA is widely used in signal processing and communication and it use prewhiting and appropriate choice of non-linearities, ICA can separate mixed signal. ANFIS controller is trained with the hybrid learning algorithm to optimize its parameters for adaptively canceling noise. This new method which minimizes a statistical dependency of mutual information(MI) in mixed low frequency noise signal and there is no need to secondary path modeling. The proposed implementations achieve more powerful and stable noise reduction than Filtered-X LMS algorithms which is needed for LTI assumption and precise secondary error

• Journal of Power Electronics
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• v.9 no.1
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• pp.26-35
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• 2009

A high efficiency active clamp sepic-flyback converter is presented for fuel cell generation systems. The proposed converter is a superposition of a sepic converter mode and. flyback converter mode. The output voltages of the sepic converter mode and flyback converter mode can be regulated by the same PWM technique with constant frequency. By merging the sepic and flyback topologies, they can share the transformer, power MOSFET and active clamp circuit. The result has outstanding advantages over conventional active clamp DC-DC converters: high efficiency, high power density, and component utilization. Simulation results and experimental results are presented to verify the principles of operation for the proposed converter.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.40 no.3
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• pp.181-188
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• 2003

In this paper, we introduce a magnetic noise shielding method to reduce the noise effects in permanent magnet based MRI systems. Through FEM electromagnetic analyses, we have shown that the magnetic noise component parallel to the main magnetic field is the major component that makes various artifacts in the images obtained with a permanent magnet based MRI. Based on the FEM analyses, we have developed an active magnetic noise shielding system composed of a magnetic field sensor, compensation coils, and a coil driving system. The shielding system has shown a noise rejection ratio of about 30dB at the frequency below several Hz. We have experimentally verified that the shielding system greatly improves the image quality in a 0.3 Tesla MRI system.

• Journal of Power Electronics
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• v.13 no.5
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• pp.861-876
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• 2013

Instead of extracting every selected harmonic component, the current reference of selective active power filter (APF) can be also obtained by filtering out the fundamental component from distorted load current for computation efficiency. This type of mixed current reference contains kinds of harmonic components and easily involves noises. In this condition, selective harmonic compensation must be realized by the current controller. With regard that selectivity is the most significant feature of controller, this paper presents specific comparison analysis between two types of resonant controllers: proportional-resonant (PR) controller and vector-resonant (VR) controller. The comparison analysis covers the relations, performances, and stability of both controllers. Analysis results conclude that the poorer selectivity of the PR controller could be relatively improved, but limitations from system stability make the improvement hardly realized. By contrast, the VR controller exhibits excellent selectivity and is more suitable for selective APF with mixed current reference. Experimental results from laboratory prototype validate the reasonability of analysis. And the features of each resonant controller are concluded.

• Korean Journal of Pharmacognosy
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• v.30 no.3
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• pp.284-289
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• 1999

In order to find active ingradients having an agonistic activity to benzodiazepine receptor from Gastrodia elata Blume (Orchidaceae) which has been used as an anticonvulsant in oriental medicine, one component and some fractions were separated from the butanol extract of the rhizomes of this plant and evaluated for their activities on GABA/benzodiazepine receptor in vitro. As a result, one crude mixture (F4f) obtained from the most active fraction (F4) inhibited significantly the binding of $[^3H]Ro15-1788$, a selective benzodiazepine receptor antagonist, to benzodiazepine receptor of rat cortices. GABA significantly enhanced the inhibition of $[^3H]flunitrazepam$ binding by F4f, and this positive GABA shift supported the strong possibility of the agonistic activity of F4f to benzodiazepine receptor.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.1
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• pp.121-125
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• 1998

The effects of various cooking methods (blanching, microwave heating, and deep-fat frying) on biologically active components of Angelica keiskei were determined by HPLC. Cynharoside, the biologically active component of Angelica keiskei leaves was 4.82%, which was rapidly decreased by blanching, showing 3.79%, 2.59% and 1.74% at 1 min, 2min and 3min, respectively. Microwave heating also decreased the cynaroside contents slowly by 2 min and rapidly by 3min, respectively. Microwave heating also decreased the cynaroside contents slowly by 2min and rapidly by 3 min, showing 4.25% at 1 min, 3.38% at 2 min, and 1.49% at 3 min. Among the cooking methods tested, deep-fat frying was shown to preserve the cynaroside most. Only 3.90% of cynaroside was lost by 5 min frying. The decrease in cynaroside in each cooking method was supposed to be due to the conversion of cynarside, a glycoside of flavonoid, into luteolin through lysis of glucose at C-7 position on cynaroside.